Python#12

Sets

Sets are used to store multiple items in a single variable

Sets are defined with {}.

Set is one of 4 built-in data types in Python used to store collections of data.

A set is a collection which is unordered, unchangeable*, and unindexed. 

Does not allow duplicate elements

set = {} will return data type as dictionary. SO we have to use set() method

to return <class: set>

Set Operations are explained in the following example code:

s1 = {}
print(type(s1))
#<class 'dict'>


s2 =set()
print(type(s2))
#<class 'set'>

s3 = set(("apple", "banana", "cherry")) # note the double round-brackets
print(s3) #{'banana', 'apple', 'cherry'}


aset ={1,2,3,4,5,5}
print(aset)
#{1, 2, 3, 4, 5}

aset =set("Hello")
print(aset)
#{'H', 'e', 'o', 'l'}   -->order immaterial, only one l is printed


aset = set()
aset.add(11)
aset.add(22)
aset.add(33)


#aset.discard()
print(aset)   #{33,11,22}
aset.pop()
print(aset)   #{11,22}

#set Operations

odd = {1, 3, 5, 7, 9}
even = {0, 2, 4, 6, 8, 10}
primes = {3, 5, 7}

print(odd.union(even)) #{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

print(odd.intersection(primes)) #{3, 5, 7}

print(even.intersection(primes))  #set()

print(odd.difference(primes)) #{1, 9}

print(odd.symmetric_difference(primes)) #{1, 9}

print(odd.symmetric_difference(even)) #{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

a = {1,2,3,4,5,6,7,8,9}

b = {1,2,3,10,11,12}

a.update(b)

print(a) # {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}

a.intersection_update(b)

print(a) #{1, 2, 3, 10, 11, 12}

a.add(13)
print(a) # {1, 2, 3, 10, 11, 12, 13}

print(b) #{1, 2, 3, 10, 11, 12}

b.pop()

print(b)   #{2, 3, 10, 11, 12}

def odd_even():
    n = int(input('EnterNumper < 10 Please'))  #5
    if n in odd:
        print('Odd number')
    elif n in even:
        print('Even number')

# odd_even() # Odd Number

print(a.issuperset(b))  # True

print(a.isdisjoint(b))   # False


c ={7,8,9}

print(a.isdisjoint(c))  # True

d = c # copy the reference be careful when u change the original alsowill change
print(c,d)  #{8, 9, 7} {8, 9, 7}
d.add(18)
print(c,d)  # {8, 9, 18, 7} {8, 9, 18, 7} dangerous original also changed


c ={7,8,9}
d = c.copy()
d.add(18)
print(c,d)   # {8, 9, 7} {8, 9, 18, 7}

The results are given in the same line as comments for easy reference and understanding.

Happy set learning with AMETODL😈😈😈